diff --git a/tortoise/utils/device.py b/tortoise/utils/device.py
index 8b31ecc..53626ee 100755
--- a/tortoise/utils/device.py
+++ b/tortoise/utils/device.py
@@ -9,7 +9,7 @@ DEVICE_BATCH_SIZE_MAP = [(14, 16), (10,8), (7,4)]
 from inspect import currentframe, getframeinfo
 import gc
 
-is_WSL = 'wsl' in os.popen("uname -r").read().tolower()
+is_WSL = 'wsl' in os.popen("uname -r").read().lower()
 
 def xpu_get_mem(device=0):
     total_memory = ipex.xpu.get_device_properties(device).total_memory